1. Field of the Invention
This invention relates to ground flare stacks and more particularly to such stacks for the burning of waste combustible gases containing various hydrocarbons.
2. Description of the Prior Art
It has heretofore been proposed to burn waste combustible gases employing successive stages to accommodate varied quantities of gas to be burned.
Nahas, in U.S. Pat. No. 3,322,178, shows a flare apparatus for staged combustion in a pit below ground level, Venturi burners being disposed along the sides of the pit.
Hoy, et al., in U.S. Pat. No. 3,881,857 show a combustor with a chamber divided into a plurality of zones having increasing numbers of air tubes so that progressively increasing areas may be ignited.
Beck, in U.S. Pat. No. 2,625,992 shows in a flat burner arrangement multiple gas burners in groups with provisions for utilizing a plurality of groups sequentially as required.
Reed et al., in U.S. Pat. No. 3,749,546, show in a flat pit burner a plurality of flow lines connected to a plurality of burners for utilization in stages, determined by the pressure of the gas.
The foregoing all require a relatively large flat surface area with the combustion exposed to view from the surrounding land area.
Pillard et al., in U.S. Pat. No. 3,885,919, show a residual gas burner with a smoke evacuating conduit at the base and a plurality of superposed coaxial combustion chambers of increasing volume with gas supplied to a number of burners varying in the same manner as the outflow of gases.
The waste gas burners of the staged type heretofore available require excessive area, do not adequately conceal the combustion glare and noise and have other shortcomings.